Nikola Tesla U.S. Patent 725,605 - System of Signaling Patent Wrapper Page 30

644 Cardwell do 9 ed to produce two or more distinctive kinds or classes of disturbances or impulses, of sensitive receiving circuits, each adapted to respond to the impulses or disturbances of one kind or class only, and a receiving device dependent for operation upon the conjoint action of the sensitive. circuits, as set forth. 1 6. In a system for the transmission of electrical impulses, and the operation or control of signalling, or other apparatus thereby, the combination with a transmitter adapted to produce two or more distinctive kinds or classes of disturbances or impulses, of sensitive circuits at the receiving point or station, each adapted to respond to the impulses or disturbances of one kind or class only, a local circuit arranged to be completed by the conjoint action of the sensitive circuits and a receiving device connected therewith, as set forth. 7. In a system for the transmission of electrical impulses and the operation or control of signalling or other apparatus thereby, the combination with a transmitting apparatus adapted to produce two or more distinctive kinds. of disturbances or impulses, of means for varying the relations of the impulses of the several kinds, sensitive circuits each adapted to respond to the impulses or disturbances of one kind only, and a receiving apparatus dependent for operation upon the conjoint action of the sensitive. circuits, as set forth. 8. In a system, such as here in described, the combination with a transmitter adapted to produce a plurality of 1 distinctive kinds of electrical disturbances or impulses, of a receiving apparatus comprising a plurality of circuits, -12